JP3298328B2 - Dielectric constant measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for measuring the dielectric constant of a dielectric such as a plastic part.

[0002]

BACKGROUND OF THE INVENTION Plastic parts used in discarded automobiles and home appliances, such as automobile bumpers,
In order to recycle the same plastic parts, it is necessary to identify the material of the discarded plastic parts, for example, whether it is a polypropylene resin or a polyurethane resin.

In order to identify the material of a plastic part,
It is conceivable to use the fact that plastic is a dielectric and has a different dielectric constant depending on the type.

Therefore, an apparatus for measuring the dielectric constant of a discarded plastic part is required.

[0005]

However, the conventional permittivity measuring apparatus measures the permittivity of a specific sample with much labor in a laboratory.

[0006] There appears to be no known dielectric constant measuring device that can easily measure the dielectric constant of a plastic part in the field where discarded plastic parts are identified for reuse.

An object of the present invention is to solve the above-mentioned conventional problems.

[0008]

According to the present invention, two arms are rotatably connected in the middle, the base ends of both arms are formed in an operation portion, and the distal ends of both arms are formed in a sandwiching portion. , Both ar
An elastic body with a center hole is interposed at the tip of
And attach a conductive rubber plate electrode with a center hole.
Attach a contact at the tip of the pinch between both arms
The two contacts in the center hole of the elastic body and the electrode respectively.
Away from the elastic body and the electrodes, and between the electrodes and the contacts
When the DUT is sandwiched between the two electrodes,
The two elastic bodies are compressed,
Are respectively configured to hit the surface of the object to be measured, and a capacitance detection unit that outputs a signal according to the capacitance between the two electrodes and a thickness detection unit that outputs a signal according to the distance between the two contacts are provided. A dielectric constant calculating unit that calculates an output signal of the capacitance detecting unit and an output signal of the thickness detecting unit and outputs a signal corresponding to a dielectric constant or a relative dielectric constant of the device under test; A dielectric constant measuring device provided with a display unit for displaying.

Further, the present invention provides the above dielectric constant measuring apparatus, wherein the elastic member and the contact arranged in the center hole of the electrode;
A dielectric constant measuring apparatus characterized in that an elastic body and a center hole of an electrode are concentric .

[0010]

In the present invention, the operating portions of both arms are operated by hand or the like to open and close the sandwiching portions of both arms, and the object to be measured is sandwiched between both electrodes and between the contacts.

Then, the capacitance C between the two electrodes sandwiching the object to be measured and the distance d between the two contacts sandwiching the object to be measured are detected, and a well-known relational expression ε = C · d / S ( S: electrode area)
The dielectric constant ε or the relative dielectric constant ε _{s of the} measured object is calculated from ε _s = ε / ε ₀ (ε ₀ : vacuum dielectric constant) and displayed on the display unit.

Namely, when sandwiching the object to be measured between the between by operating the operation portion of the electrodes both contacts, the dielectric constant epsilon or relative permittivity epsilon _s of the object to be measured is measured.

In the present invention, even when the surface of the object to be measured hitting the electrode is a curved surface, the electrode and the elastic body of the conductive rubber plate are deformed following the surface of the object to be measured and the electrode is measured. since close contact with the surface of the object, the dielectric constant epsilon or relative permittivity epsilon _s of the object to be measured is measured.

[0014]

According to the present invention, the dielectric constant or relative permittivity of an object to be measured can be easily measured by sandwiching the object to be measured between both electrodes and between both contacts.

Therefore, the dielectric constant of the plastic part can be easily measured at the site where the discarded plastic part is identified for reuse, and the material of the plastic part can be easily identified.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIGS. 1 and 2, a dielectric constant measuring apparatus according to this embodiment includes a pivot 3 connected between two arms 1 and 2 made of light alloy.
The two arms 1 and 2 are rotatably connected to each other, and the base end side of the pivots 3 of the arms 1 and 2 is formed as an operating part 4 that can be gripped with one hand. Has formed. As shown in FIG. 2, between the base ends of the holding portions 5 of the arms 1 and 2.
And a helical spring 6 as shown in FIG.

When the operating portions 4 of the arms 1 and 2 are gripped and approached by one hand, the holding portions 5 of the arms 1 and 2 are opened against the helical spring 6 as shown by a chain line in FIG. When the force of gripping the operation unit 4 of both arms 1 and 2 is reduced, the sandwiching portion 5 of both arms 1 and 2 is closed by the contraction force of the extended spiral spring 6.

As shown in FIGS. 1 and 2, a thick square sponge elastic body 7 having a center hole in a square plane facing each other is coaxially bonded to the tip of the sandwiching portion 5 of both arms 1 and 2. Then, electrodes 8 of a thin square conductive rubber plate having a center hole are respectively adhered concentrically to both sponge elastic members 7, and both electrodes 8 are arranged at positions facing each other.

As shown in FIG. 1, screw contacts 9 made of a hard material such as a metal and having a screw shaft are concentrically provided on the ends of the sandwiching portions 5 of the arms 1 and 2 as shown in FIG. The two contactors 9 are arranged concentrically in the center holes of the sponge elastic body 7 and the electrode 8, respectively, and are separated from the sponge elastic body 7 and the electrode 8, so that the adjustable protrusion length of the two contactors 9 is adjusted. Each of the contacts 9 is slightly shorter than the total thickness of the sponge elastic body 7 and the electrode 8, and
Are arranged in the center hole.

In other words, when the operating part 4 of the arms 1 and 2 is operated with one hand and the waste plastic part of the object to be measured is sandwiched between the electrodes 8, the electrodes 8 come into close contact with the surface of the object to be measured, respectively. Then, both sponge elastic bodies 7 are compressed, and both contacts 9 are configured to contact the surface of the object to be measured.

When the surface of the object to be measured which the electrode 8 hits is a curved surface, the electrode 8 of the conductive rubber plate and the sponge elastic body 7 are deformed following the surface of the object to be measured, and the electrode 8 is measured. It is configured to be in close contact with the surface of the object.

As shown in FIGS. 1 and 3, displacement gauges 10 and 11 are mounted between the base ends of the holding portions 5 of the arms 1 and 2. The displacement meter has a linear potentiometer 10 fixed to the holding portion 5 of the upper arm 1, a block 11 fixed to the holding portion 5 of the lower arm 2, and a movable detection axis of the linear potentiometer 10 applied to the block 11. The resistance between the two output terminals of the linear potentiometer 10 changes according to the distance between the terminals 9, that is, the thickness of the object to be measured.

As shown in FIG. 1, both electrodes 8 are connected to a capacitance detecting section 13 by electric wires 12, respectively. The capacitance detection unit 13 is an electric circuit that outputs a signal corresponding to the capacitance C between the electrodes 8.

As shown in FIG. 1, both output terminals of the linear potentiometer 10 are connected to a thickness detector 15 by electric wires 14, respectively. The thickness detecting section 15 includes the two contacts 9.
It is an electric circuit that outputs a signal according to the distance d between the two.

The capacitance detecting unit 13 and the thickness detecting unit 15
Are connected to the permittivity calculating unit 16 as shown in FIG. The permittivity calculating unit 16 converts a signal corresponding to the capacitance C between the electrodes 8 and a signal corresponding to the distance d between the contacts 9 into a well-known relational expression ε = C · d / S (S: electrode Area = 16c
m ² ) ε _s = ε / ε ₀ (ε ₀ : vacuum permittivity = 8.854)
× substituted into ^{10-2 12} [F / m]) is an electrical circuit for outputting seek signal corresponding to the dielectric constant epsilon or relative permittivity epsilon _s of the object to be measured.

As shown in FIG. 1, the permittivity calculating section 16
It is connected to the display unit 17. The display unit 17 displays the dielectric constant ε or the relative dielectric constant ε of the DUT output by the dielectric constant calculation unit 16.
_This is a device that displays a signal corresponding to _s .

When the dielectric constant measuring apparatus of this embodiment is used, the operating part 4 of both arms 1 and 2 is operated with one hand, and the waste plastic of the object to be measured is placed between the electrodes 8 and the contacts 9. Insert the parts.

Then, the capacitance C between the electrodes 8 sandwiching the object to be measured and the distance d between the two contacts 9 sandwiching the object to be measured are detected, and the dielectric constant ε or relative dielectric constant of the object to be measured is detected. The rate ε _s is calculated and displayed on the display unit 17.

Even when the surface of the object to be measured which the electrode 8 hits is a curved surface, the electrode 8 of the conductive rubber plate and the sponge elastic body 7 are deformed following the surface of the object to be measured, and the electrode 8 is measured. since close contact with the surface of the object, the dielectric constant epsilon or relative permittivity epsilon _s of the object to be measured is measured.

FIG. 4 shows an example in which the relative permittivity of various waste plastic parts was measured using the permittivity measuring apparatus of this embodiment. As is clear from FIG. 4, the measured values of the relative dielectric constants of the polypropylene resin, the acrylic resin, and the polyurethane resin are as follows:
Although the value slightly varies depending on the difference between the resin maker and the production lot, the value is a nominal value of the relative dielectric constant generally published or a value close to the nominal value.

<Modification> In the embodiment, the measured value of the dielectric constant or the relative dielectric constant of the object to be measured is displayed on the display unit 17. A comparison circuit is provided between the arithmetic unit 16 and the display unit 17 using the intermediate value of the dielectric constant of both plastic parts as a reference value. The display unit 17 is composed of two lamps.
A signal corresponding to the dielectric constant of the device under test output from is input to a comparison circuit and compared with a reference value, and one or the other of the lamps of the display unit 17 is turned on depending on whether it is higher or lower than the reference value.

[Brief description of the drawings]

FIG. 1 is a front view of a dielectric constant measuring apparatus according to an embodiment of the present invention.

FIG. 2 is a plan view of the dielectric constant measuring device of the same example.

FIG. 3 is a sectional view taken along line AA of FIG. 1;

FIG. 4 is a diagram showing a measurement example of the dielectric constant measuring apparatus of the same example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Upper arm 2 Lower arm 4 Operation part 5 Nipping part 7 Elastic sponge 8 Electrode of a conductive rubber plate 9 Contact 13 Capacitance detection part 15 Thickness detection part 16 Dielectric constant calculation part 17 Display part

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-85770 (JP, A) JP-A 57-86469 (JP, U) JP-A 61-182807 (JP, U) (58) Investigation Field (Int.Cl. ⁷ , DB name) G01R 27/26 G01B 5/06 G01B 7/06

Claims (2)

(57) [Claims] The two arms are rotatably connected in the middle, the base ends of both arms are formed in an operation section, the distal ends of both arms are formed in a sandwiching section, and the distal ends of the sandwiching sections of both arms are formed. Elastic body with center hole on each
Attach a conductive rubber plate electrode with a center hole through
Contact each other at the tip of the pinch between both arms.
Attach both contacts in the center hole of the elastic body and electrode respectively
And separated from the elastic body and the electrode,
When the object to be measured is sandwiched between the probes, both electrodes
The two elastic bodies are compressed,
Each of the contacts is configured to contact the surface of the device under test, and a capacitance detection unit that outputs a signal according to the capacitance between the two electrodes and a thickness detection unit that outputs a signal according to the distance between the two contacts. A dielectric constant calculation unit that calculates an output signal of the capacitance detection unit and an output signal of the thickness detection unit and outputs a signal corresponding to a dielectric constant or a relative dielectric constant of the device under test; A dielectric constant measuring device comprising a display unit for displaying a signal. 2. A contact arranged in a center hole of an elastic body and an electrode.
2. The dielectric constant measuring apparatus according to claim 1, wherein the element, the elastic body and the center hole of the electrode are concentric .